AAT1161IWO-0.6-T1 View Datasheet(PDF) - Analog Technology Inc
Part Name
Description
MFG CO.
'AAT1161IWO-0.6-T1' PDF : 18 Pages View PDF
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PRODUCT DATASHEET
AAT1161
13.2V Input, 3A Step-Down Converter
Design Example
Specifications
VOUT
VIN
FOSC
TAMB
5V @ 3A, Pulsed Load ∆ILOAD = 3A
12V nominal
800kHz
85°C in TDFN34-16 Package
Output Inductor
L1 =
VOUT · (VIN
VIN · ∆IL
-
·
VOUT)
FOSC
=
3.8µH;
see
Table
2.
∆IL = 0.32 · ILOAD
For Coilcraft inductor MSS1038 3.8µH DCR = 13mΩ max.
∆I1 =
VOUT
L1 ⋅ FOSC
⋅
⎛⎝1
-
VO1
VIN
⎞
⎠
=
5V
3.8µH ⋅ 800kHz
⋅
⎛⎝1
-
5V ⎞
12V⎠
=
959mA
IPK1
=
ILOAD
+
∆I1
2
=
3A
+
0.479A
=
3.48A
PL1
=
I2
LOAD
⋅
DCR
=
3A2
⋅
13mΩ
=
117mW
Output Capacitor
VDROOP = 0.2V
COUT
=
3 · ∆ILOAD
VDROOP · FOSC
=
3 · 3A
0.2V · 800kHz
= 56µF; use three 22µF
I = RMS(MAX)
1 · (VOUT) · (VIN(MAX) - VOUT) = 1 ·
2· 3
L · FOSC · VIN(MAX)
2· 3
5V · (12V - 5V)
3.8µH · 800kHz · 12V
= 277mArms
Pesr = esr · IRMS2 = 5mΩ · (277mA)2 = 384µW
1161.2008.03.1.0
www.analogictech.com
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